A flow divider valve is disclosed in U.S. Pat. No. 3,500,854, for use in a vehicle wherein a hydraulic circuit for power steering purposes is provided and a second hydraulic circuit for power takeoff in a tractor, excavator, shovel loader, or the like. The flow divider valve is likewise required to provide a power steering circuit with a primary conveying flow, only the excess being used for power takeoff. Inasmuch as the flow for power steering is needed only during steering, it is only at that time that flow distribution from the valve is effected, in response to the amount of flow required, which is dependent on the angle of turn. Accordingly, for load dependent distribution of flow, the regulating piston is provided with a throttling point in the feed line to the hydraulic circuit to be provided with pressure fluid. Furthermore, such regulating piston is loaded by a spring against the pressure from a feed-in bore. Therefore, due to differential forces acting at opposite ends of the regulating piston, the valve shifts against the force of the spring dependent on such pressure difference whereby flow control edges of the valve can release pressure flow to a second hydraulic circuit for power takeoff.
Flow divider valves have a hydraulic response corresponding to the passage arrangement for flow and regulation which corresponds to the degree of opening of the flow control edges.
There are at least two flow control edge regulating positions which are changed in either of the hydraulic circuits corresponding to pressure buildup. High pressure differences, however, lead to a heating up of the pressure oil and to losses of energy which have a negative effect on the energy balance of the flow divider valve. Accordingly, as low as possible a pressure difference is desirable. If, however, it is desired to reduce the pressure difference or the resistance of pressure oil flowing through the valve, it is necessary for the flow control edges of the regulating piston coacting with the housing to effect a large flow gap when open. The result is that in a pressure buildup contained in either hydraulic circuit large movements of the regulating piston are necessary. Such large movements delay pressure buildup and also cause flow oscillations and strong flow pulsations. It is also advantageous where large flows are desired through circuit passages, high pressures are required dependent on the position of a regulating piston relative to the housing, viz., the degree of separation of the valve and housing coacting flow control edges to effect flow gaps.